Locations for good accommodation at relatively modest price and school

Hi my wife and I are looking to relocate to vienna. We will be looking for a small apartment. Min 45m square. Can anyone please advise as to best locations for good accommodation but relatively modest price. Can anyone also please advise on a good school for intense german language study.

1st and 19th districts I would avoid, they are super expensive. 

But you have to look around, the public transport system in Vienna is great so where you live you can be anywhere in minutes.